Internet and Web

5.1 INTRODUCTION TO COMPUTER NETWORKS

In today's connected world, information is produced, exchanged, and traced globally in real time due to the interconnection of digital entities. A network is defined as a group of two or more similar things or people interconnected with each other. Networks are prevalent in everyday life, such as social networks, mobile networks, computer networks, and networks in airlines, railways, banks, and hospitals. Specifically, a computer network is an interconnection among two or more computers or computing devices that allows sharing of data and resources. The size of a network can vary from a few computers in a room to millions of devices spread worldwide. Hosts or nodes in a network can be servers, desktops, laptops, or mobile devices. Data communication in networks is achieved by dividing data into smaller chunks called packets, which are transmitted over wired or wireless media. Nodes in a network include any device capable of receiving, creating, storing, or sending data, such as modems, hubs, switches, routers, printers, or computers. The interconnectivity enables simultaneous information exchange through emails, websites, audio/video calls, and resource sharing like printers or storage. Personal networks can be created using hotspots, connecting devices wirelessly in a small area.

• A network is a group of interconnected similar entities.
• Computer networks connect two or more computing devices for data and resource sharing.
• Network size varies from small (few devices) to large (millions of devices).
• Nodes include devices like servers, desktops, laptops, mobile phones, modems, hubs, switches, routers, and printers.
• Data is transmitted in packets over wired or wireless media.
• Networks enable simultaneous communication and resource sharing.
• 📌 Network: A group of interconnected similar entities.
• 📌 Computer Network: Interconnection of two or more computers for sharing data and resources.
• 📌 Node: Any device in a network that can receive, create, store, or send data.

5.2 TYPES OF NETWORKS

Computer networks vary widely in size, coverage area, and data transfer rates. Based on geographical coverage and speed, networks are broadly classified into Local Area Network (LAN), Metropolitan Area Network (MAN), and Wide Area Network (WAN). A LAN connects devices within a limited area such as a room, office, or campus, typically up to 1 km. It uses wired media like Ethernet cables or wireless media like Wi-Fi. LANs are secure and provide high data transfer rates ranging from 10 Mbps (Ethernet) to 1000 Mbps (Gigabit Ethernet). Ethernet is a set of rules governing LAN communication. MAN covers a larger area such as a city or town, extending up to 30-40 km. It is an extended form of LAN and often formed by connecting multiple LANs. Cable TV networks and broadband services are examples of MAN. WAN connects computers and networks spread over large geographical areas, including countries and continents. WANs connect multiple LANs and MANs via wired or wireless media. The Internet is the largest example of a WAN, connecting billions of devices worldwide. These networks enable communication, resource sharing, and access to global information.

• LAN connects devices within a limited area (up to 1 km) with high data transfer rates.
• MAN covers a city or town area, extending up to 30-40 km, connecting multiple LANs.
• WAN connects networks over large geographical areas, including countries and continents.
• Ethernet is the protocol set used in LANs for wired communication.
• Data transfer rates decrease from LAN to MAN to WAN.
• The Internet is the largest WAN connecting millions of networks globally.
• 📌 LAN (Local Area Network): Network covering a small geographical area.
• 📌 MAN (Metropolitan Area Network): Network covering a city or town.
• 📌 WAN (Wide Area Network): Network covering large geographical areas across countries or continents.